If you have an Anti-virus like AVIRA or AVG it certenly blocked changes to localhost by adding the "::1" entry in the HOSTS file in c:\windows\system32\drivers\etc\HOSTS
All you have to do is to remove this line (::1) or just comment it by adding "#" sign in front of it in the hosts file.

I had the same issue and I tried all of the above with no results.
Then, I re-install the WampServer (deleting the wamp folder manually), and this worked, but finally I caught what was wrong in my case...

I made a change on the http.conf file, I un-commented this>

# Virtual hosts
Include conf/extra/httpd-vhosts.conf

And then I opened the un-commented file to add my virtual host, but forgot to add one for the local host...
So, just by adding this in the httpd-vhosts.conf file>